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2874c5fd28
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
164 lines
3.2 KiB
C
164 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* SNAP data link layer. Derived from 802.2
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*
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* Alan Cox <alan@lxorguk.ukuu.org.uk>,
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* from the 802.2 layer by Greg Page.
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* Merged in additions from Greg Page's psnap.c.
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*/
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <net/datalink.h>
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#include <net/llc.h>
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#include <net/psnap.h>
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#include <linux/mm.h>
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#include <linux/in.h>
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#include <linux/init.h>
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#include <linux/rculist.h>
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static LIST_HEAD(snap_list);
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static DEFINE_SPINLOCK(snap_lock);
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static struct llc_sap *snap_sap;
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/*
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* Find a snap client by matching the 5 bytes.
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*/
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static struct datalink_proto *find_snap_client(const unsigned char *desc)
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{
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struct datalink_proto *proto = NULL, *p;
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list_for_each_entry_rcu(p, &snap_list, node) {
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if (!memcmp(p->type, desc, 5)) {
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proto = p;
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break;
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}
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}
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return proto;
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}
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/*
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* A SNAP packet has arrived
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*/
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static int snap_rcv(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *pt, struct net_device *orig_dev)
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{
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int rc = 1;
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struct datalink_proto *proto;
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static struct packet_type snap_packet_type = {
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.type = cpu_to_be16(ETH_P_SNAP),
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};
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if (unlikely(!pskb_may_pull(skb, 5)))
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goto drop;
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rcu_read_lock();
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proto = find_snap_client(skb_transport_header(skb));
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if (proto) {
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/* Pass the frame on. */
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skb->transport_header += 5;
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skb_pull_rcsum(skb, 5);
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rc = proto->rcvfunc(skb, dev, &snap_packet_type, orig_dev);
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}
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rcu_read_unlock();
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if (unlikely(!proto))
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goto drop;
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out:
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return rc;
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drop:
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kfree_skb(skb);
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goto out;
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}
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/*
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* Put a SNAP header on a frame and pass to 802.2
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*/
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static int snap_request(struct datalink_proto *dl,
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struct sk_buff *skb, u8 *dest)
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{
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memcpy(skb_push(skb, 5), dl->type, 5);
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llc_build_and_send_ui_pkt(snap_sap, skb, dest, snap_sap->laddr.lsap);
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return 0;
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}
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/*
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* Set up the SNAP layer
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*/
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EXPORT_SYMBOL(register_snap_client);
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EXPORT_SYMBOL(unregister_snap_client);
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static const char snap_err_msg[] __initconst =
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KERN_CRIT "SNAP - unable to register with 802.2\n";
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static int __init snap_init(void)
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{
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snap_sap = llc_sap_open(0xAA, snap_rcv);
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if (!snap_sap) {
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printk(snap_err_msg);
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return -EBUSY;
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}
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return 0;
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}
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module_init(snap_init);
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static void __exit snap_exit(void)
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{
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llc_sap_put(snap_sap);
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}
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module_exit(snap_exit);
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/*
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* Register SNAP clients. We don't yet use this for IP.
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*/
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struct datalink_proto *register_snap_client(const unsigned char *desc,
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int (*rcvfunc)(struct sk_buff *,
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struct net_device *,
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struct packet_type *,
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struct net_device *))
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{
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struct datalink_proto *proto = NULL;
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spin_lock_bh(&snap_lock);
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if (find_snap_client(desc))
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goto out;
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proto = kmalloc(sizeof(*proto), GFP_ATOMIC);
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if (proto) {
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memcpy(proto->type, desc, 5);
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proto->rcvfunc = rcvfunc;
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proto->header_length = 5 + 3; /* snap + 802.2 */
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proto->request = snap_request;
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list_add_rcu(&proto->node, &snap_list);
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}
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out:
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spin_unlock_bh(&snap_lock);
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return proto;
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}
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/*
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* Unregister SNAP clients. Protocols no longer want to play with us ...
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*/
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void unregister_snap_client(struct datalink_proto *proto)
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{
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spin_lock_bh(&snap_lock);
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list_del_rcu(&proto->node);
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spin_unlock_bh(&snap_lock);
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synchronize_net();
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kfree(proto);
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}
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MODULE_LICENSE("GPL");
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